Abstract:
Reef islands are low-lying accumulations of unconsolidated sediments that are located on coral atolls in mid-ocean settings. Reef islands are initially formed by wave processes that transports sediment across the reef structure and is deposited on the reef surface. Low lying reef islands are vulnerable to the impacts of climate change and sea level rise, as they are sensitive to environmental shifts. Reef islands are able to adapt to shifts in conditions, such as changes in sea level and sediment supply. Field measurements of island morphology and sediment samples were taken on Tepuka Island, Funafuti atoll, Tuvalu. Results show that the sediments from the island are composed predominantly of foraminifera, coralline algae and coral, whereas the reefflat is composed of predominantly coralline algae and corals. The stratigraphic profile of Tepuka Island shows that the material that is found in the layers of subsurface sediments is also found on the contemporary beach and reef-flat surface. The similarities of the sediments suggest that there is an active linkage between the island and reef, and that the sediments found on Tepuka Island are still being actively being supplied to the island. The linkage between the island and reef is important in the sedimentological aspects of reef island formation and development.